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Class 10 Triangles worksheet
CBSE Mathematics. Similar triangles, the Basic Proportionality Theorem, AA, SSS and SAS. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
In △ABC, DE ∥ BC with D on AB and E on AC. If AD = 1 cm, DB = 3 cm and AE = 2 cm, then EC is:
- 6 cm
- 2/3 cm
- 8 cm
- 7 cm
Answer
(a) 6 cm
AD/DB = AE/EC: 1/3 = 2/EC, so EC = 6
- 2.
△ABC ~ △PQR with AB = 8 cm, BC = 20 cm and PQ = 10 cm. Then QR is:
- 16 cm
- 20 cm
- 29 cm
- 25 cm
Answer
(d) 25 cm
QR/BC = PQ/AB = 5/4, so QR = 20 × 5/4 = 25
- 3.
△ABC ~ △DEF. AB = 8 cm, DE = 2 cm and the perimeter of △ABC is 84 cm. The perimeter of △DEF is:
- 23 cm
- 84 cm
- 21 cm
- 105 cm
Answer
(c) 21 cm
perimeters are in the ratio of corresponding sides: 84 × 1/4 = 21
Section B · short answer
- 4.
In △ABC, DE ∥ BC. If AD = x + 2, DB = x + 4, AE = x − 1 and EC = x (in cm), find x.
Answer
x = 4
AD/DB = AE/EC: (x + 2)(x) = (x + 4)(x − 1), which gives x = 4
- 5.
△ABC ~ △PQR. AB = 15 cm, BC = 20 cm, CA = 30 cm and PQ = 12 cm. Find QR and RP.
Answer
QR = 16 cm, RP = 24 cm
scale factor PQ/AB = 4/5
Section C · long answer
- 6.
A vertical pole 3 m tall casts a shadow 10 m long. At the same time, a tower casts a shadow 90 m long. How tall is the tower?
Answer
27 m
the sun's rays make similar triangles: height/90 = 3/10
Fresh sheets for your child
In the app, every Triangles sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
Coming soon for Android and iPhone.